Composite Carbon Fiber Bicycle Crank and Its Method of manufacture

ABSTRACT

A method of manufacture of forming a composite carbon fiber bicycle crank includes providing a hollow carbon fiber body, with the body including a first opening at one end and the second opening at the other end, mounting a first connecting member and a second connecting member in the first opening and the second opening of the body respectively, wrapping carbon fiber yarn made up of carbon yarn around the assembly of the body and the first and second connecting members, wrapping carbon fiber polymer, and performing hot embossing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a bicycle crank and its method of manufacture, in particular, to a composite carbon fiber bicycle crank which copies the principle of how tendon connecting muscle with a bone and its method of manufacture.

2. Description of the Related Art

In order to build a lighter bicycle, compound steel and aluminum alloy have been utilized in place of metal for the manufacture of the bicycle cranks.

Referring to FIG. 9, a conventional bicycle crank 90 made of aluminum includes a metal strip 901 having a first end and a second end, a first axle fastening member 902 and a second axle fastening member 903, with the first end adjacent to the first axle fastening member 902, and with the second end adjacent to the second axle fastening member 903. The metal strip 901, the first axle fastening member 902, and the second axle fastening member 903 are wrapped with a composite material 904.

Referring to FIG. 10, another conventional bicycle crank 91 made of polyurethane foam includes a polyurethane body 911 having a first end and a second end, a first axle fastening member 912 and a second axle fastening member 913, with the first axle fastening member 912 having the polyurethane body 911 extended therethrough and being disposed in proximate to the first end, and with the second axle fastening member 913 adjacent to the second end. The polyurethane body 911, the first axle fastening member 912 and the second axle fastening member 913 are wrapped with a composite material 914. This bicycle crank 91 is lighter than the bicycle crank 90.

FIG. 11 illustrates another conventional bicycle crank 92 in which a first axle fastening member 921 and a second axle fastening member 922 are wrapped by composite materials 923 and 924, inserted into a bag 925 made of nylon, and high pressure air is bled into the bag 925 before conducting hot embossing processes. This bicycle crank 92 is the lightest among the three recited prior arts. However, manufacturing the bicycle crank 92 is troublesome. Also, the structure is weak near the opening of the bag 925.

The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art

SUMMARY OF THE INVENTION

A method of manufacture of forming a composite carbon fiber bicycle crank includes providing a hollow carbon fiber body, with the body including a first opening at one end and the second opening at the other end, mounting a first connecting member and a second connecting member in the first opening and the second opening of the body respectively, wrapping carbon fiber yarn around the assembly of the body and the first and second connecting members, wrapping carbon fiber polymer, and performing hot embossing.

It is an objective of the present invention to provide a method of manufacture for forming a robust and light weighted bicycle crank.

It is another objective of the present invention to provide a bicycle crank which is aesthetically pleasing.

Other objectives, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For the present disclosure to be easily understood and readily practiced, the present disclosure will now be described for the purpose of illustration not limitation, in conjunction with the following figures, wherein;

FIG. 1 is a process flow chart illustrating the various steps of manufacturing a bicycle crank of the present invention.

FIG. 2 is an exploded perspective view of the bicycle crank of the present invention not being wrapped by carbon fiber yarn and carbon fiber polymer.

FIG. 3 is a perspective view illustrating the wrapping of the carbon fiber yarn.

FIG. 4 is a perspective view illustrating the bicycle crank of the present invention wrapped in carbon fiber yarn.

FIG. 5 is a perspective view illustrating the bicycle crank of the present invention wrapped in carbon fiber polymer.

FIG. 6 is a process flow chart illustrating various steps of manufacturing a bicycle crank in accordance with the second embodiment of the present invention.

FIG. 7 is perspective illustrating a bicycle crank in accordance with the second embodiment of the present invention.

FIG. 8 is a side, cross-sectional view of the bicycle crank shown in FIG. 7 FIG. 9 is a side, cross-sectional view of a conventional bicycle crank.

FIG. 10 is a side, cross-sectional view of another conventional bicycle crank.

FIG. 11 is an exploded perspective view of another conventional bicycle crank.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, there is shown a method of manufacture of a bicycle crank in accordance with the present invention. The method includes providing a body 10 made of carbon fiber, mounting a first connecting member 20 and a second connecting member 30 to the body 10, wrapping carbon fiber yarn 40 around the assembly of the body 10 and the first and second connecting members 20, 30, wrapping carbon fiber polymer 50, and conducting hot embossing.

Referring to FIGS. 2 through 5, the body 10 is hollow and includes a first opening 11 at one end for receiving the first connecting member 20, a second opening 13 at another end for receiving the second connecting member 30. The body 10 also includes a first groove 12 and a second groove 14 recessed into the outer surface thereof, wherein the first and second grooves 12, 14 are intercrossed and both grooves extend from the first opening 11 to the second opening 13.

The first connecting member 20 and the second connecting member 30 are made of metal. The first connecting member 20 includes a locking rib 21 and a plurality of protrusions 22 extending radially from the periphery thereof The locking rib 21 prevents the first connecting member 20 from moving with respect to the body 10. The protrusions 22 of the first connecting member 20 are arranged circumferentially and symmetrically, and a passage 23 is defined between the protrusions 22. The second connecting member 30 includes a locking rib 31 and a plurality protrusions 32 extending radially from the periphery thereof. The locking rib 31 prevents the second connecting member 30 from moving with respect to the body 10.

Now turning our attention back to FIG. 1, having disposed first connecting member 20 within the opening 11 and the second connecting member 30 within the opening 13, the assembly is wrapped by carbon fiber yarn 40 in which yarns are laid at 0 degree. Also, as best seen from FIGS. 4 and 5, the carbon fiber yarn 40 is wrapped on the first and second grooves 12, 14 of the body 10, the protrusions 22 and the passage 23 of the first connecting member 20, and the protrusions 32 of the second connecting member 30, so that the first and second connecting members 20, 30 are tightly attached to the body 10. The carbon fiber polymer 50 is disposed over the assembly of the first and second connecting members 20, 30 and the body 10 and the carbon fiber yarn 40 before conducting hot embossing. During hot embossing, resin is used.

Referring to FIG. 6, there is shown a process flow chart of a method of manufacture of forming a bicycle crank in accordance with the second embodiment of the present invention, wherein the bicycle crank is similar to the first embodiment expect that it includes a five fastening fingers 60 attached thereto. The method includes providing the body 10 made of carbon fiber, mounting the first connecting member 20 and the second connecting member 30 to the body 10, wrapping the carbon fiber yarn 40 around the assembly of the body 10 and the first and second connecting members 20, 30, mounting the five fastening fingers 60 to the assembly, wrapping the carbon fiber polymer 50, and conducting hot embossing.

Therefore, in one aspect of the composite carbon fiber bicycle crank and its method of manufacture, the hollow carbon fiber body 10 and composite materials such as the carbon fiber yarn 40 and the carbon fiber polymer 50 help provide a light-weight structure. In another aspect of the present invention, the carbon fiber yarn 40 is wrapped on the first and second grooves 12,14 of the body 10, the first connecting member 20 and second connecting member 30, and the carbon fiber polymer 50 is wrapped over thereafter so as to a provide a strong construction of the bicycle crank. In yet another aspect of the present invention, the bicycle crank can also include a five fastening fingers 60 attached thereto. In yet another aspect of the present invention, the first and second grooves 12, 14 of the body 10 receiving the carbon fiber yarn 30 are intercrossed, accordingly, the carbon fiber yarn 30 is diagonally disposed on the body 10 and the first connecting member 20 and the second connecting member 30 are not susceptible to detach from the body 10. It is yet another aspect of the present invention, the bicycle crank requires no troublesome work to make it aesthetically pleasing.

While the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of invention and the scope of invention is only limited by the scope of accompanying claims. 

1. A method of manufacture of forming a composite carbon fiber bicycle crank comprising: providing a hollow carbon fiber body, with the body including a first opening at one end and the second opening at the other end, mounting a first connecting member and a second connecting member in the first opening and the second opening of the body respectively, wrapping carbon fiber yarn around the assembly of the body and the first and second connecting members, wrapping carbon fiber polymer, and conducting hot embossing.
 2. The method of manufacture of forming a composite carbon fiber bicycle crank as claimed in claim 1 includes mounting a five fastening fingers to the assembly of the body and the connecting members.
 3. The method of manufacture of forming a composite carbon fiber bicycle crank as claimed in claim 1 wherein the body includes a first groove and a second groove recessed into the outer wall thereof, with the first groove and the second groove being intercrossed, and with the first groove and the second groove extending from the first opening to the second opening.
 4. The method of manufacture of forming a composite carbon fiber bicycle crank as claimed in claim 2 wherein the body includes a first groove and a second groove recessed into the outer wall thereof, with the first groove and the second groove being intercrossed, and with the first groove and the second groove extending from the first opening to the second opening.
 5. The method of manufacture of forming a composite carbon fiber bicycle crank as claimed in claim 1 wherein the first connecting member includes a locking rib extending radially from the periphery thereof the second connecting member includes a locking rib extending radially from the periphery thereof, wherein the locking rib of the first connecting member prevents the first connecting member from moving with respect to the body, the locking rib of the second connecting member prevents the second connecting member from moving with respect to the body.
 6. The method of manufacture of forming a composite carbon fiber bicycle crank as claimed in claim 2 wherein the first connecting member includes a locking rib extending radially from the periphery thereof the second connecting member includes a locking rib extending radially from the periphery thereof, wherein the locking rib of the first connecting member prevents the first connecting member from moving with respect to the body, the locking rib of the second connecting member prevents the second connecting member from moving with respect to the body.
 7. The method of manufacture of forming a composite carbon fiber bicycle crank as claimed in claim 1 wherein the first connecting member includes a plurality of protrusions extending radially from the periphery thereof, the second connecting member includes a plurality protrusions extending radially from the periphery thereof, the protrusions of the first connecting member are arranged circumferentially and symmetrically, with a passage being defined between the protrusions, the carbon fiber yarn being arranged at 0 degree, with the carbon fiber yarn being wrapped around the first and second grooves, the protrusions and the passage of the first connecting member and the protrusions of the second connecting member.
 8. The method of manufacture of forming a composite carbon fiber bicycle crank as claimed in claim 2 wherein the first connecting member includes a plurality of protrusions extending radially from the periphery thereof the second connecting member includes a plurality protrusions extending radially from the periphery thereof the protrusions of the first connecting member are arranged circumferentially and symmetrically, with a passage being defined between the protrusions, the carbon fiber yarn is arranged at 0 degree, with the carbon fiber yarn being wrapped around the first and second grooves, the protrusions and the passage of the first connecting member and the protrusions of the second connecting member.
 9. A composite carbon fiber bicycle crank comprising: a hollow carbon fiber body, with the body including a first opening at one end and the second opening at the other end; a first connecting member disposed in the first opening and a second connecting member disposed in the second opening; carbon fiber yarn is disposed on the outer wall of the body and the first and second connecting members around the periphery thereof, carbon fiber polymer is disposed over the said carbon fiber yarn.
 10. A composite carbon fiber bicycle crank as claimed in claim 9 includes a five fastening fingers connected to the body at one end;
 11. A composite carbon fiber bicycle crank as claimed in claim 9 wherein the body includes a first groove and a second groove recessed into the outer surface thereof, with the first and second grooves being intercrossed, and with the groove extending from the first opening to the second opening.
 12. A composite carbon fiber bicycle crank as claimed in claim 10 wherein the body includes a first groove and a second groove recessed into the outer surface thereof, with the first and second grooves being intercrossed, and with the groove extending from the first opening to the second opening.
 13. A composite carbon fiber bicycle crank as claimed in claim 9 wherein the first connecting member includes a locking rib extending radially from the periphery thereof, the second connecting member includes a locking rib extending radially from the periphery thereof, wherein the locking rib of the first connecting member prevents the first connecting member from moving with respect to the body, the locking rib of the second connecting member prevents the second connecting member from moving with respect to the body.
 14. A composite carbon fiber bicycle crank as claimed in claim 10 wherein the first connecting member includes a locking rib extending radially from the periphery thereof, the second connecting member includes a locking rib extending radially from the periphery thereof, wherein the locking rib of the first connecting member prevents the first connecting member from moving with respect to the body, the locking rib of the second connecting member prevents the second connecting member from moving with respect to the body.
 15. A composite carbon fiber bicycle crank as claimed in claim 9 wherein the first connecting member includes a plurality of protrusions extending radially from the periphery thereof; the second connecting member includes a plurality protrusions extending radially from the periphery thereof, the protrusions of the first connecting member are arranged circumferentially and symmetrically, with a passage being defined between the protrusions, the carbon fiber yarn is arranged at 0 degree, with the carbon fiber yarn being wrapped around the first and second grooves, the protrusions and the passage of the first connecting member and the protrusions of the second connecting member.
 16. A composite carbon fiber bicycle crank as claimed in claim 10 wherein the first connecting member includes a plurality of protrusions extending radially from the periphery thereof, the second connecting member includes a plurality protrusions extending radially from the periphery thereof, the protrusions of the first connecting member are arranged circumferentially and symmetrically, with a passage being defined between the protrusions, the carbon fiber yarn is arranged at 0 degree, with the carbon fiber yarn being wrapped around the first and second grooves, the protrusions and the passage of the first connecting member and the protrusions of the second connecting member. 